Have you ever wondered how the Rebel Alliance acquired the intelligence about the fatal flaw in the Death Star that gave Luke Skywalker the opportunity to target the doomsday weapon’s weak spot so perfectly in the original “Star Wars” (now known, of course, as “Star Wars IV: A New Hope”?)

Well, whether or not that question has haunted you for nearly forty years, “Rogue One: A Star Wars Story,” provides the answer. It’s an immediate prequel to “Hope,” or if you prefer a sort of “Rosenkrantz and Guildenstern Are Dead” for the Lucas crowd, providing a nearly-parallel story that links up perfectly with the plot of the 1978 blockbuster. Along the way it offers glimpses of old friends and foes from earlier installments, a few in the person of real-life actors doing cameos, and others through elaborate CGI effects, including some that resuscitate human beings no longer with us for a posthumous curtain call (or make people look far younger than they actually are).

The result should please long-time fans since the movie is efficiently made, with the combination of breathless action and juvenile humor the series has always delivered, while eschewing the kid-friendly elements that became increasingly dominant with “Return of the Jedi.” But it comes across as an assembly-line product, an elaborate but fairly conventional action-adventure movie too dependent for its effect on references to earlier entries in the series.

It’s also—like “The Force Awakens”—a girly “Star Wars,” with a kick-ass female protagonist. Perhaps that’s a sign of the Disney imprimatur, which seems more and more inclined to emphasize strong young woman as the centerpieces (think of “Tangled,” or “Frozen,” or “Moana,” or even “Zootopia”). In this case she’s Jyn Erso, who as a young girl watches as her mother is killed and her father Galen (Mads Mikkelsen), a brilliant scientist turned simple farmer, carted off by imperial weapons honcho Orson Krennic (Ben Mendelsohn) to work on the Death Star. The scene is not unlike the invasion of Tatooine at the start of “Hope,” the event that leads to Luke’s adventures.

Years later Jyn (Felicity Jones) has grown into a rough-and-tumble survivor, skilled at taking care of herself. But in an encounter with her erstwhile mentor Saw Gerrera (Forest Whitaker), she sees a hologram of her father—another echo of “Hope”—that informs her of a design flaw he’s secretly imbedded in the Death Star. Taking advantage of it, however, will require the acquisition of a complete blueprint from the well-protected imperial weapons archive. When the leaders of the Alliance balk at undertaking such a dangerous mission, she assembles an “unofficial” crew of volunteers to do the job–Cassian Andor (Diego Luna), an intense undercover agent who’s come to believe in her; K-2S0 (voiced by Alan Tudyk), the erstwhile imperial droid that’s now Cassian’s cynical partner; Bodhi Rook (Riz Ahmed), an imperial pilot turned nervous rebel; Chirrut Imwe (Donnie Yen), a blind ex-Jedi; and his surly companion and protector Baze Malbus (Jiang Wen).

This dirty half-dozen—“Rogue One” is a pretty grimy movie—proceed to the tropical enclave that houses the empire’s weapons development facility, where Jyn hopes to reconnect with her father. That will happen, at least after a fashion, but most of the scenario there will be devoted to taking on an army of stormtroopers and breaking into the official files to retrieve Galen’s schematics of the Death Star—a sort of oversized flash drive—for transmittal to the Alliance. The long battle sequence is replete with close shaves, daring escapes, sudden reversals, acts of self-sacrifice and a sudden intervention by friends (no “Star Wars” movie worth its salt would do without plenty of combat between armadas of space ships), but ultimately the entire scenario comes down to a protracted sci-fi version of pictures like “The Guns of Navarone,” in which a ragtag bunch of heroes take on a presumably invincible foe to destroy a weapon of unimaginable magnitude. The result, it should be noted, would appear to be a “Rogue One”-shot, as the list of major characters lost in action is pretty long.

But frankly that’s less of a problem than it might seem, simply because the characters aren’t terribly memorable. Jones gives tomboyish Jyn a charge of energy but not much personality, and as played by Luna and Ahmed the two men in her crew are relatively bland. Yen and Jiang are more crowd-pleasing as Chirrut and Baze, given the touch of deadpan humor they bring to the roles, but one can’t escape the feeling that both were added to the mix to appeal to the ever-growing Asian market. In the laugh department, moreover, they’re certainly outshone by K-2S0, who gets most of the best lines, which Tudyk delivers with accomplished timing. In terms of villainy, meanwhile, Mendelsohn is no Darth Vader.

Purely as product the picture is a well-oiled machine, with director Gareth Edwards marshalling his cast and a top-notch technical crew—cinematographer Greg Fraser, production designers Doug Chiang and Neil Lamont, costumers Glyn Dillon and David Crossman and editors John Gilroy, Colin Goudie and Jabez Olssen, along with the visual effects team led by John Knoll and Mohen Leo—to make even the CGI-created humans (not to mention the various aliens, war machines and futuristic sets) fit in seamlessly with the live action, even if those fabricated humans don’t always look completely natural. Michael Giacchino contributes a workmanlike score, but it’s telling that the most memorable moments in it are the snatches of John Williams’ motifs from the earlier movies in the series. That’s true of the whole of “Rogue One”—the biggest charge its target audience is likely to get out of it involves those elements that refer back to previous installments and characters remembered from them. (Newcomers won’t get the allusions at all, of course, and kids below the age of ten or so will probably find the picture rather too dark and somber for their liking.)

The larger problem, of course, is that of potential overexposure. There’s no doubting the overwhelming popularity of the “Star Wars” franchise, but “Rogue” makes one wonder whether Disney’s intention to produce a plethora of spin-offs, prequels and tangentially related movies—not to mention sequels to last year’s reboot—will ultimately hobble the golden goose. As the Marvel superhero movies have shown, today’s audience seems to have an insatiable appetite for the familiar delivered repeatedly in barely new packaging, so perhaps the aggregated “Star Wars” can go on indefinitely. But maybe not. “Rogue One” is an okay space opera, but already it feels a little dated, and you have to wonder whether the Mouse House’s ambitious plan for its expensive acquisition might not make the galaxy far, far away too frequent a destination except for the most rabid fan.